Acetylcholinesterase activity in partially isolated cerebral cortex after prolonged intermittent stimulation.

Acetylcholinesterase (AChE) levels were determined in control samples of cat cerebral cortex, in partially neuronally isolated (undercut) cortex, and in undercut or intact cortex that had received long-term intermittent electrical stimulation. Assay of AChE activity was based on an automatic titration method using methalcholine as substrate. Tissues from ten of 15 undercut cerebral cortices showed the expected decrease in AChE. Long-term intermittent electrical stimulation of undercut cortex prevented the expected decrease in AChE in seven of 12 cortices. Previous data showed that similar long-term stimulation could prevent some electrical manifestations of supersensitivity. The present findings implicate, in part, a cholinergic system in the phenomenon of cortical supersensitivity.